Flujo de potencia óptimo con restricciones de estabilidad

Debido a cambios considerables en las redes eléctricas, como el aumento de la conexión de generación distribuida, la evaluación de los impactos de estas generaciones en la red eléctrica se vuelve más relevante. Estas evaluaciones pueden realizarse con diferentes enfoques, como la evaluación del funcionamiento en estado estable, la calidad del voltaje, la respuesta transitoria del generador conectado a la red, etc. En este contexto, los algoritmos de flujo de potencia óptimo restringido por estabilidad transitoria se han utilizado cada vez más. Dichos algoritmos permiten la optimización de parámetros de estado estacionario y, además, la evaluación de las respuestas transitorias angulares de los generadores conectados a la red. Sin embargo, el principal desafío técnico para resolver estos algoritmos se refiere a la alta dimensionalidad de la solución. Para reducir el problema de dimensionalidad, el presente trabajo aplica los dos análisis de estabilidad de escala, que se basan en una característica intrínseca de los sistemas eléctricos, la coexistencia de diferentes respuestas dinámicas en el mismo sistema. Por lo tanto, los algoritmos propuestos se unen a un algoritmo de flujo de potencia óptimo restringido por estabilidad transitoria con el enfoque de dos escalas de tiempo, lo que permite la aplicación de modelos generadores más complejos sin comprometer la dimensionalidad del problema. Además, se desarrolló un clasificador de contingencia para redes de máquinas múltiples con el propósito de elegir la contingencia de flujo de potencia óptima. El algoritmo implementado completo se probó en un sistema de distribución real de 32 boquillas y presentó resultados satisfactorios en el contexto de la optimización del problema modelado, y también redujo la dimensionalidad del sistema en comparación con el problema original, sin aplicar el enfoque de dos escalas de tiempo. El clasificador de contingencia permite un análisis crítico de las contingencias más relevantes a tener en cuenta y presenta los resultados de forma intuitiva. El algoritmo de flujo de potencia óptimo con restricción de estabilidad transitoria presentó resultados consistentes considerando varios pesos de función objetivo. También se verificó la estabilidad angular transitoria para ambos subsistemas. Y finalmente, se logró una reducción considerable de la dimensionalidad del problema debido a la aplicación del enfoque de dos escalas de tiempo, en comparación con el problema original.Brasil. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Capes)Trabajo de investigació

Importancia de la Participación de los Padres de Familia en las Instituciones de Educación Inicial

El trabajo de investigación lleva el título “participación de los padres de familia de las instituciones educativas del nivel inicial” nace del interés de conocer la participación de los padres, por ello, el objetivo general: Describir la participación que tiene los padres de familia en el desarrollo del aprendizaje de los niños del nivel inicial, y el método de nivel descriptivo exploratorio, es un tipo de compilación. Se concluye al final la importancia de la participación en el desarrollo de los aprendizajes significativos de los niño

Programa Reactiva Perú para la restablecer la liquidez de la empresa JKMB Generales SRL, Chimbote 2020

Para el desarrollo de la siguiente investigación tuvo como objetivo de estudio fundamentar la contribución del Programa Reactiva Perú en el restablecimiento de la liquidez de la empresa JKMB Generales SRL, Chimbote 2020, es de tipo descriptiva simple – no experimental, de forma aplicativa; se tuvo como muestra de la población de estudio a la contadora de la empresa JKMB Generales SRL, donde se realizó la técnica de recolección de datos en una entrevista y la guía de análisis documental. Del cual se tuvo como resultado en la entrevista que la empresa por medio del programa Reactiva Perú, mejoró su liquidez afectada por la pandemia del Covid 19, por el cual la empresa pudo hacer frente a sus obligaciones a corto plazo. Pudieron cubrir sus obligaciones, como además tener fondos para una inversión extra en la empresa, creando nuevos ingresos y una mejor rentabilidad. Y la guía de análisis documental que mediante el estudio de sus cuentas para el análisis de la liquidez denotamos que la empresa mejoró su liquidez mediante el programa Reactiva Perú

Association among salivary alpha-amylase activity and executive functioning in healthy children

Salivary alpha-amylase (sAA) is employed in basic research as a surrogate and non-invasive marker of the activity of Autonomous Nervous System (ANS) and Adrenomedullar System (AMS). In particular, sAA has showed a statistically sig- nificant association with levels of peripheral noradrenaline under acute psychoso- cial stress conditions in young and healthy participants. In this study, our aim was directed to describe the relation among sAA and cognitive performance in differ- ent executive tasks in a sample composed by 69 healthy children (45 boys). The tasks employed to assess executive functioning belong to the ENFEN battery (which measures different aspects of executive functions through four subtests: Phonologic and Semantic Fluency, Trail Making Test, Towers, and Interference). Saliva samples were obtained at baseline (10 minutes before the start of neuro- psychological assessment), just one minute before and just one minute after the end of the last subtest of ENFEN. Our statistical analyses showed a direct and sig- nificant association among sAA and scores in Phonologic Fluency, Trail Making, Towers and Interference subtests of ENFEN after controlling the effect of BMI. These results show a positive lineal association among sAA and executive behav- ior in healthy children. We discuss these findings in relation with those studies what have suggested a main role of the noradrenergic central action mediated via Locus Coeruleus-Noradrenaline System (LC-NA System) in the regulation of executive behavior.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Association among salivary alpha-amylase activity and working memory functioning in healthy children

Salivary Alpha-Amylase (sAA) shows a statistically significant association with levels of peripheral noradrenaline under acute psychosocial stress conditions in young and healthy participants. In this study, our aim was directed to examine the relation among sAA and cognitive performance in various executive tasks in an experimental sample composed by 69 healthy children although we only could obtain the complete set of data for 44 boys and girls for this battery. The cogni- tive tasks employed were: Digits, Letters & Numbers, Arithmetic and Visual Span subtests of WISC-V (this full set of subtests is employed to the assessment of verbal and visual working memory). Saliva samples were obtained at baseline (10 minutes before the start of neuropsychological assessment), one minute before the start, after the end of the verbal tasks, and one minute after the end of the visual span task. Our statistical analyses showed a significant association among sAA levels and some of the parameters employed to describe the perfor- mance of each participant in the subscales of Digits and Letters & Numbers after controlling the effect of BMI. Scores in Letters & Numbers and visual span were associated with levels of salivary flow rate. These results are coherent with the findings of a previous pilot study conducted in our laboratory and are interpreted in relation with those results which have suggested a main role of the Locus Coeruleus-Noradrenaline System (LC-NA System) in the regulation of the level of arousal and executive behaviors.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Relic galaxy analogues in TNG50 simulation : the formation pathways of surviving red nuggets in a cosmological simulation

Relic galaxies are massive compact quiescent galaxies that formed at high-redshift and remained almost unchanged since then. In this work, we search for analogues to relic galaxies in the TNG50 cosmological simulations to understand relic formation and test the ability of TNG50 to reproduce such rare objects. Using stellar mass, age, radius, quiescence, and stellar assembly criteria, we find five subhaloes in TNG50 that could be potential relic analogues. We compare their properties with other constraints imposed by a sample of 13 observed relic galaxies. We find one analogue in TNG50 that simultaneously satisfies most of the available observational constraints, such as metallicity and morphology. It also shows similarities to the confirmed relic NGC 1277, regarding environment and dark matter fraction. By taking into account a degree of relicness, a second relic analogue may also be considered. However, the central parts of the brightness and density profiles of the analogues are less steep than that of real relic galaxies, possibly due to limited numerical resolution. We identify two formation pathways of relic analogues in TNG50 depending on their environment: they either have their remaining gas stripped during the infall into a cluster at z 1.2 or consume it before z > 1.5. They are then deprived of significant star formation, leaving their stellar populations almost unaltered during the last 9 Gyr. We also find that the analogue progenitors at z ∼ 4 inhabit more massive haloes than progenitors of quiescent galaxies with similar stellar mass at z ∼ 0

Globular cluster systems of relic galaxies

We analyse the globular cluster (GC) systems of a sample of 15 massive, compact early-type galaxies (ETGs), 13 of which have already been identified as good relic galaxy candidates on the basis of their compact morphologies, old stellar populations and stellar kinematics. These relic galaxy candidates are likely the nearby counterparts of high-redshift red nugget galaxies. Using F814W (≈I) and F160W (≈H) data from the WFC3 camara onboard the Hubble Space Telescope, we determine the total number, luminosity function, specific frequency, colour, and spatial distribution of the GC systems (GCSs). We find lower specific frequencies (SN < 2.5 with a median of SN = 1) than ETGs of comparable mass. This is consistent with a scenario of rapid, early dissipative formation, with relatively low levels of accretion of low-mass, high-SN satellites. The GC half-number radii are compact, but follow the relations found in normal ETGs. We identify an anticorrelation between the specific angular momentum (λR) of the host galaxy and the (I − H) colour distribution width of their GCSs. Assuming that λR provides a measure of the degree of dissipation in massive ETGs, we suggest that the (I − H) colour distribution width can be used as a proxy for the degree of complexity of the accretion histories in these systems

Globular Cluster Systems of Relic Galaxies

We analyse the globular cluster (GC) systems of a sample of 15 massive, compact early-type galaxies (ETGs), 13 of which have already been identified as good relic galaxy candidates on the basis of their compact morphologies, old stellar populations and stellar kinematics. These relic galaxy candidates are likely the nearby counterparts of high redshift red nugget galaxies. Using F814W (~I) and F160W (~H) data from the WFC3 camara onboard the Hubble Space Telescope we determine the total number, luminosity function, specific frequency, colour and spatial distribution of the GC systems. We find lower specific frequencies (SN<2.5 with a median of SN=1) than ETGs of comparable mass. This is consistent with a scenario of rapid, early dissipative formation, with relatively low levels of accretion of low-mass, high-SN satellites. The GC half-number radii are compact, but follow the relations found in normal ETGs. We identify an anticorrelation between the specific angular momentum (lambda_R) of the host galaxy and the (I-H) colour distribution width of their GC systems. Assuming that lambda_R provides a measure of the degree of dissipation in massive ETGs, we suggest that the (I-H) colour distribution width can be used as a proxy for the degree of complexity of the accretion histories in these systems.Comment: MNRAS accepte